English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We determine the sensitivity to a possible variation of theproton-to-electron mass ratio \mu for torsion-wagging-rotation transitions inthe ground state of methylamine (CH3NH2). Our calculation uses an effectiveHamiltonian based on a high-barrier tunneling formalism combined withextended-group ideas. The \mu-dependence of the molecular parameters that areused in this model are derived and the most important ones of these arevalidated using the spectroscopic data of different isotopologues ofmethylamine. We find a significant enhancement of the sensitivity coefficientsdue to energy cancellations between internal rotational, overall rotational andinversion energy splittings. The sensitivity coefficients of the differenttransitions range from -19 to +24. The sensitivity coefficients of the 78.135,79.008, and 89.956 GHz transitions that were recently observed in the disk of az = 0.89 spiral galaxy located in front of the quasar PKS 1830-211 [S. Mulleret al. Astron. Astrophys. 535, A103 (2011)] were calculated to be -0.87 for thefirst two and -1.4 for the third transition, respectively. From thesetransitions a preliminary upper limit for a variation of the proton to electronmass ratio of \Delta \mu/\mu< 9 x 10^{-6} is deduced.

Sensitivity to a possible variation of the Proton-to-Electron Mass Ratio of Torsion-Wagging-Rotation Transitions in Methylamine (CH3NH2)